Study of EPN-701 for the Treatment of Calciphylaxis

Inclusion Criteria: 1. Participant must provide written or electronic consent after the nature of the study has been explained, and prior to any research-related procedures, per the International Conference on Harmonization (ICH) Good Clinical Practice (GCP) 2. Clinical diagnosis of calciphylaxis confirmed by the Investigator with presence of at least one ulcerated skin lesion and moderate or severe pain (worst pain intensity in the preceding 24 hours of at least 5 on a 0-10 scale). Consistent with the clinical practice and expert recommendations, histological confirmation of calciphylaxis diagnosis by a skin biopsy is not a requirement for participation. 3. ESKD requiring thrice weekly hemodialysis 4. Male or female aged ≥18 years 5. Women of childbearing potential (WOCBP) as defined in Clinical Trials Facilitation and Coordination Group (CTFG, 2020) must have a negative serum pregnancy test (defined as serum hCG ≤25 mIU/mL \[Haninger-Vacariu, 2020\]) at Screening 6. Women of childbearing potential (WOCBP) must be using or agree to use one highly effective form of contraception and a barrier method from Screening through 30 days after the last dose of study treatment. See Appendix C for further information about highly effective forms of contraception. 7. Males who are sexually active must agree to use condoms from the period following first dose of study treatment through four weeks after the last dose of study treatment. Males with a WOCBP partner must agree to use one highly effective form of contraception in addition to condoms from Screening through 30 days after the last dose of study treatment. 8. Males must agree to not donate sperm from the period following the first dose of study treatment through 4 weeks after last dose of study treatment. WOCBP who are participants or partners of fertile male participants must agree not to donate ova from the period following the first dose of study treatment through 4 weeks after last dose of study treatment. Exclusion Criteria: 1. In the opinion of the Investigator, presence of any clinically significant disease outside of calciphylaxis that may impact study participation and/or confound interpretation of the study results 2. Hospitalized at the time of Screening. Patients discharged from a hospital admission ≥24 hours prior to Screening may be eligible for participation. 3. Septic shock 4. Hospice or comfort care including withdrawal from dialysis 5. Malignancy within the last year, except non-melanoma skin cancers, cervical carcinoma in situ, or localized prostate cancer. 6. Concurrent participation in another interventional clinical study and/or receipt of any other investigational new drug within four weeks prior to the first dose of study treatment, or use of an investigational device, through completion of participation in the study 7. Previous participation in a study of EPN-701 8. Participants who are pregnant, trying to become pregnant, or breastfeeding 9. Participants who are trying to father a child 10. Peritoneal dialysis participants 11. Kidney transplant recipients who are receiving immunosuppression at the time of Screening and patients who have an imminent transplant plan. Patients who have received a kidney transplant that has failed, necessitating dialysis, and who are no longer on immunosuppression may participate. 12. History of or current diagnosis of cirrhosis 13. Current use of prohibited medications, including vitamin K-containing medications and warfarin. Patients who have discontinued warfarin treatment upon the diagnosis of calciphylaxis will be eligible for Screening.